Download Manual - Hach Chlorine Reagent Set (Total)

Chlorine, Total, 10014
Chlorine, Total
DOC316.53.01032
USEPA DPD Method1
Method 10014
ULR (2 to 500 µg/L as Cl2)
Pour-Thru Cell and OriFlo™ Filtration
Scope and Application: For testing trace levels of chlorine and chloramines in treated domestic and industrial
wastewater; USEPA accepted for reporting for wastewater analysis2
1
Adapted from Standard Methods for the Examination of Water and Wastewater.
2
U.S. Patent 5,362,650 covers the procedure. U.S. Patent 5,549,816 covers the OriFlo™ Filtration System.
Test preparation
How to use instrument-specific information
The Instrument-specific information table displays requirements that may vary between
instruments. To use this table, select an instrument then read across to find the corresponding
information required to perform this test.
Table 118 Instrument-specific information
Pour-thru Kit
Cell orientation1
Adapter
DR 6000
LQV175.99.20002
Arrow faces right
—
DR 5000
LZV479
—
—
DR 3900
LQV157.99.10002
Align cell flow arrows with arrows on cell compartment
—
5940400
1-inch (round) path aligned with arrow on the adapter
LZV585 (B)
Instrument
DR 3800, DR 2800, DR 2700
1
Align for long path
Before starting the test:
Analyze samples immediately. Samples containing chlorine cannot be preserved for later analysis.
A reagent blank value for a combined lot of indicator/buffer reagent solutions should be determined at least once a day. If
sample color or turbidity fluctuates frequently during the day, determine a reagent blank for each sample. Refer to Treating
Analysis Labware on page 7.
The reagent blank value is normally less than 5 µg/L. If the value is greater than 5 µg/L, an interfering substance may be
present in the blanking water or the DPD Indicator may be degrading. If there is doubt about the reagents, repeat the reagent
blank determination using chlorine-demand-free water for the sample. Blanks up to 5 µg/L may be used.
Use a new filter for each test. Using an unspecified filter may give low analysis results or inability to filter the required volume.
Ampules contain more than 1.0 mL of solution for ease of transfer. Discard excess reagent in the ampule.
Refer to the instrument User Manual for Pour-Thru cell and module assembly and installation.
Protect the Pour-Thru Cell from contamination when not in use by inverting a small beaker over the top of the glass funnel.
Use forceps to handle filters.
Make sure the Pour-Thru cell is completely seated in the sample cell compartment.
Chlorine, Total
Page 1 of 10
Chlorine, Total
Collect the following items:
Description
Quantity
ULR Chlorine Buffer Solution, 1.5-mL ampules
1 mL
DPD Indicator Solution for ULR Chlorine, 1.5-mL ampules
1 mL
Blanking Reagent for ULR Chlorine
1 mL
Membrane Filters, 3-micron, 25-mm
1
OriFlo Assembly
1
Beaker, 250 mL
1
Cylinder, graduated mixing, 50-mL.
1
Pipet, TenSette®, 0.1 to 1.0 mL
1
Pipet Tips
2
Deionized water
Varies
Ampule Breaker
1
Pour-Thru Module and cell
1
See Consumables and replacement items for reorder information.
DPD method for Pour-Thru Cell
Stored Programs
86 Chlorine Total, ULR
Start
1. Select the test.
Insert an adapter if
required (Instrumentspecific information).
Chlorine, Total
Page 2 of 10
2. Flush the Pour-Thru
cell with 50 mL of
deionized water.
3. Unscrew the cap from
the OriFlo™ plunger
assembly. Be sure that the
O-ring is properly seated
in the cap.
4. Install a new, 3-micron
filter (white) into the cap
well. Wet the filter with a
few drops of deionized
water. Reassemble and
hand-tighten the cap onto
the plunger.
Chlorine, Total
DPD method for Pour-Thru Cell (continued)
5. Open one ULR
Chlorine Buffer Solution
Ampule.
6. Using a TenSette®
Pipet and a clean tip,
transfer 1.0 mL of buffer
from the ampule to a
clean, treated 50-mL
graduated mixing cylinder.
7. Open one ampule of
DPD Indicator Solution for
Ultra Low Range Chlorine.
8. Use a TenSette Pipet
and a clean tip to transfer
1.0 mL of indicator from
the ampule to the
graduated mixing cylinder.
Swirl to mix.
Proceed to step 9 within
one minute.
9. Prepared Sample:
Avoiding extra agitation,
carefully fill the cylinder to
the 50-mL mark with
sample. Stopper the
cylinder. Gently invert it
twice to mix.
10. Press TIMER>OK.
A three-minute reaction
time will begin. Perform
steps 11–16 during this
period.
Measure the reacted
sample 3–6 minutes after
mixing the sample and
reagents. If less than three
minutes elapses, the
reaction with chloramines
may be incomplete. A
reading after six minutes
may result in higher
reagent blank values.
11. Push the valve button
on the OriFlo™ barrel
assembly in (“closed”
position). Place the barrel
assembly into its stand.
Pour approximately 50 mL
of the original sample into
the barrel.
12. Insert the plunger into
the barrel and slowly push
the plunger down with
even pressure, until the
plunger is fully seated.
The lower ring on the
barrel assembly
represents about a 50-mL
volume.
Chlorine, Total
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Chlorine, Total
DPD method for Pour-Thru Cell (continued)
Zero
13. Pour the filtered
sample from the plunger
reservoir into the
Pour-Thru Cell.
14. When the flow stops,
ZERO the instrument.
The display will show:
0 µg/L Cl2.
15. Pull the barrel valve
button out to the “open”
position. Pull the plunger
up to separate it from the
barrel assembly. Discard
the remaining unfiltered
sample.
16. Push the barrel valve
button to the “closed”
position. Place the barrel
assembly into its stand.
A new membrane may be
required for very turbid
samples. Alternatively, use
a second Quick Filter unit
with a new membrane filter
installed.
17. When the timer
expires, pour the contents
of the mixing cylinder into
the barrel.
18. Insert the plunger into
the barrel and slowly push
the plunger down with
even pressure, until the
plunger is fully seated.
19. Pour the filtered,
reacted sample from the
plunger reservoir into the
Pour-Thru Cell.
20. Flush the Pour-Thru
Cell with at least 50-mL of
deionized water
immediately after use.
READ the results in µg/L
chlorine.
Subtract the reagent blank
value (See Determining
the reagent blank value)
from the sample value
obtained in step 19.
If a dechlorinating agent
(e.g., sulfite or sulfur
dioxide) is present, the
sample result, corrected
for the reagent blank, will
read “0” or a slightly
negative value.
Chlorine, Total
Page 4 of 10
Chlorine, Total
Determining the reagent blank value
Stored Programs
86 Chlorine Total ULR
Start
1. Select the test.
Make sure that the reagent
blank setting is off.
See the user manual for
information.
2. Install the Pour-Thru
module.
Flush the Pour-Thru cell
with 50 mL of deionized
water.
3. Collect about 100 mL
of deionized or tap water
in a clean, 250-mL beaker.
4. Use a TenSette® Pipet
to add 1.0 mL of Blanking
Reagent to the beaker.
Swirl several times to mix.
The Blanking Reagent
removes chlorine and
chloramines from the
water.
Note: The solution from step
4 will be used in Step 10.
5. Access the general
timer and set it for five
minutes. Start the timer.
6. After the timer expires,
open one ampule of ULR
Chlorine Buffer Solution.
7. Use a TenSette Pipet
and a clean tip to transfer
1.0 mL of buffer from the
ampule a clean 50 mL
mixing graduated cylinder.
8. Open one ampule of
DPD Indicator Solution for
Ultra Low Range Chlorine.
Chlorine, Total
Page 5 of 10
Chlorine, Total
Determining the reagent blank value (continued)
9. Use a TenSette Pipet
and a clean tip to transfer
1.0 mL of indicator from
the ampule to the cylinder.
Swirl to mix the reagents.
Proceed to step 10 within
one minute.
10. Fill the cylinder to the
50-mL mark with
dechlorinated water from
step 4. Cap and invert
twice to mix. Save the
remaining water for
step 12.
11. Start the instrument
timer.
14. When the timer
expires, pour the contents
of the cylinder into the
Pour-Thru Cell. READ the
results in µg/L chlorine.
15. Use this value to
correct the sample result
obtained in this procedure.
A three-minute reaction
time will begin.
12. During the reaction
period, flush the Pour-Thru
Cell with the remainder of
original dechlorinated
water from step 10.
Zero
13. When the flow stops,
ZERO the instrument.
The display will show:
0 µg/L Cl2.
Chlorine, Total
Page 6 of 10
See the user manual for
details on saving the
reagent blank value.
16. Flush the Pour-Thru
Cell with at least 50-mL of
deionized water
immediately after use.
Chlorine, Total
Interferences
Table 119 Interfering substances and levels
Interfering substance
Interference levels and treatments
Bromine, Br2
Interferes at all levels.
Chlorine Dioxide, ClO2
Interferes at all levels
Chloramines, organic
May interfere
Copper, Cu2+
Greater than 1000 µg/L
Iodine, I2
Interferes at all levels.
Manganese, oxidized (Mn4+,
Mn7+) or Chromium, oxidized
(Cr6+)
1.
Adjust sample pH to 6 –7 with 1.0 N Sulfuric Acid1.
2.
3.
Add 9 drops Potassium Iodide (30 g/L)1 to an 80-mL sample.
Mix and wait 1 minute.
4.
5.
6.
Add 9 drops Sodium Arsenite1, 2 (5 g/L) and mix.
Analyze the treated sample as described in the procedure above.
Subtract the result of this test from the original analysis to obtain the correct
concentration.
Nitrite, NO2– (uncommon in
clean waters)
Ozone
Interferes at all levels.
Peroxides
May interfere
Extreme sample pH or highly
buffered samples
Adjust to pH 6–7
mg/L nitrite
Apparent µg/L chlorine
2.0 mg/L
3 µg/L
5.0 mg/L
5 µg/L
10.0 mg/L
7 µg/L
15.0 mg/L
16 µg/L
20.0 mg/L
18 µg/L
1
See Optional reagents and apparatus.
2
Samples treated with sodium arsenite for interferences will be hazardous waste as regulated by the Federal RCRA for arsenic (D004). Refer
to the current MSDS for safe handling and disposal instructions.
Sample collection, storage and preservation
•
Analyze samples for chlorine immediately after collection. Chlorine is a strong oxidizing agent
and it is unstable in natural waters. It reacts rapidly with various inorganic compounds and
more slowly oxidizes organic compounds. Many factors, including reactant concentrations,
sunlight, pH, temperature and salinity influence decomposition of chlorine in water.
•
Avoid plastic containers. These may have a large chlorine demand.
•
Pretreat glass sample containers to remove any chlorine demand by soaking in a dilute bleach
solution (1 mL commercial bleach to 1 liter of deionized water) for at least 1 hour.
•
Rinse thoroughly with deionized or distilled water. If sample containers are rinsed thoroughly
with deionized or distilled water after use, only occasional pre-treatment is necessary.
•
A common error in testing for chlorine is not obtaining a representative sample. If sampling
from a tap, let the water flow for at least 5 minutes to ensure a representative sample. Let the
container overflow with the sample several times, then cap the sample containers so there is
no head space (air) above the sample.
Chlorine, Total
Page 7 of 10
Chlorine, Total
•
Perform the chlorine analysis immediately.
Treating analysis labware
Glassware used in this test must be chlorine demand-free. Fill the mixing cylinder and sample
container with a dilute solution of chlorine bleach prepared by adding 1 mL of commercial bleach
to 1 liter of water. Soak in this solution at least one hour. After soaking, rinse thoroughly with
deionized water and allow to dry before use.
Treat the Pour-Thru Cell similarly with dilute bleach and let stand for several minutes. Rinse
several times with deionized water.
Cleaning the Pour-Thru cell
The Pour-Thru Cell may accumulate a buildup of colored reaction products, especially if the
reacted solutions are allowed to remain in the cell for long periods after measurement. Remove
the buildup by rinsing the cell with 5.25 N Sulfuric Acid* followed by several rinsings with
deionized water.
Accuracy check
Required for accuracy check:
•
Low Range Chlorine Voluette® Ampule Standard Solution, 25 to 30-mg/L
(25,000 to 30,000 µg/L) Cl2
•
TenSette® Pipet and Pipet Tips
•
Ampule Breaker
Standard additions method (samples spike)
1. After reading test results, leave the sample cell (unspiked sample) in the instrument.
2. Select Options>More>Standard Additions from the instrument menu.
3. Default values for standard concentration, sample volume, and spike volumes can be
accepted or edited. Enter the chlorine concentration from the ampule package. After values
are accepted, the unspiked sample reading will appear in the top row. See the user manual for
more information.
4. Snap the top off a Low Range Chlorine Voluette® Ampule Standard Solution, 25 to 30-mg/L
(25,000 to 30,000 µg/L).
5. Prepare three sample spikes. Use the TenSette® Pipet to add 0.1, 0.2, and 0.3 mL of standard
to three 50-mL samples, respectively. Swirl gently to mix.
6. Analyze each sample spike as described in the procedure above, starting with the 0.1 mL
sample spike. Accept each standard additions reading by pressing READ. Each addition
should reflect approximately 100% recovery.
7. After completing the sequence, press GRAPH to view the best-fit line through the standard
additions data points, accounting for the matrix interferences. Press IDEAL LINE to view the
relationship between the sample spikes and the “Ideal Line” of 100% recovery.
* See Optional reagents and apparatus.
Chlorine, Total
Page 8 of 10
Chlorine, Total
Method performance
Program
86
Standard
295 µg/L Cl2
Precision
95% Confidence Limits of
Distribution
290–300 µg/L Cl2
Sensitivity
Concentration change
per 0.010 Abs change
Portion of Curve
Concentration
Entire range
17 µg/L Cl2
Summary of method
Several modifications to the normal DPD chlorine method are necessary to measure trace levels
of chlorine. The Pour-Thru Cell must be used in the spectrophotometer. Liquid reagents are also
required. The reproducible optics of the Pour-Thru Cell give more stable readings than is possible
with movable sample cells, resulting in more stable measurements.
It is essential that interfering sample turbidity is removed using a 3-micron membrane filter. To
avoid chlorine loss, the filtration is done after reacting the DPD with the chlorine in the sample. The
filter used has been specifically selected to avoid retention of the colored product. Sample color is
compensated by zeroing the spectrophotometer on a filtered sample.
The reagents are packaged in ampules and sealed under argon gas to ensure stability. Use of
liquid reagents eliminates any slight turbidity that might be caused by using powdered reagents.
Due to the possible oxidation of the reagents (which could give a positive chlorine reading in the
blank), a reagent blank must be determined at least once a day for each lot of reagent used. This
reagent blank value is subtracted from the sample result and the corrected value is the actual
chlorine concentration. Test results are measured at 515 nm.
Chlorine, Total
Page 9 of 10
Chlorine, Total
Consumables and replacement items
Required reagents
Description
Quantity/Test
ULR Chlorine Reagent Set (approximately 20 tests), includes:
Unit
Catalog number
2563000
—
—
ULR Chlorine Buffer Solution, 1.5-mL ampules
1 mL
20/pkg
2493120
DPD Indicator Solution for ULR Chlorine, 1.5-mL ampules
1 mL
20/pkg
2493220
1 mL
29 mL
2493023
varies
4L
27256
Blanking Reagent for ULR Chlorine
Water deionized
Required apparatus
Description
Quantity
ULR Chlorine Apparatus Set, includes:
Unit
Catalog number
—
—
2595600
Membrane Filters, 3-micron, 25-mm
1
25/pkg
2594025
OriFlo™ Assembly
4966000
1
each
Beaker, 250-mL
1
each
50046H
Breaker, ampule
1
each
2484600
Cylinder, graduated mixing, 50-mL
1
each
189641
Pipet, TenSette®, 0.1 to 1.0 mL
1
each
1970001
Pipet Tips, for TenSette Pipet 1970001
2
50/pkg
2185696
Unit
Catalog number
20/pkg
2630020
Recommended standards
Description
Chlorine Standard Solution,
Voluette®
Ampule, 25–30 mg/L, 2-mL
Optional reagents and apparatus
Description
Forceps, flat square tips, 115 mm
Potassium Iodide, 30 g/L
Sodium Arsenite, 5 g/L
Sulfuric Acid, 1 N 100 mL
Sulfuric Acid, 5.25 N
FOR TECHNICAL ASSISTANCE, PRICE INFORMATION AND ORDERING:
In the U.S.A. – Call toll-free 800-227-4224
Outside the U.S.A. – Contact the HACH office or distributor serving you.
On the Worldwide Web – www.hach.com; E-mail – techhelp@hach.com
© Hach Company, 2007, 2010, 2012. All rights reserved. Printed in the U.S.A.
Unit
Catalog number
each
1453700
100 mL MDB
34332
100 mL
104732
100 mL MDB
127032
1000 mL
244953
HACH COMPANY
WORLD HEADQUARTERS
Telephone: (970) 669-3050
FAX: (970) 669-2932
Edition 7